US1166824A

US1166824A - Horizontal telemeter.

Info

Publication number: US1166824A
Application number: US4812915A
Authority: US
Inventors: Otto Eppenstein
Original assignee: Carl Zeiss SMT GmbH
Current assignee: Carl Zeiss SMT GmbH; Carl Zeiss AG
Priority date: 1915-08-30
Filing date: 1915-08-30
Publication date: 1916-01-04
Anticipated expiration: 1933-01-04

Description

O. EPPENSTEIN. HORIZONTAL vTELEn/HaTER. APPLICATION FILED AUG-30. |915.

OTTO EPPENSTEIN, OF JENA, GERMANY, ASSIGN'OR. T0 THE FIB/IVI 0F CARL ZEISS, 0F

- JENA, GERMANY.

HORIZONTAL TELEMETER.

Specification of Letters Patent.,

'Patented J an. 4,191.6.

Application filed August 30, l1915. Serial No. 48,129.

1o all whom t may concern;

Be itknown that I, 'r'ro EPPENSTEIN, a citizen of the German Empire, residing at Jena, Germany, have invented a new and useful Horizontal Telemeter, of which the following is a specification.

The present invention relates to the horizontal telemeters with the base-line in the instrument7 forming the subject of Patent 1,118,337. In the telemeters according `to the said patent each of the two ray pencil systems belonging to the ends of the baseline passes besides through the respect1ve objective'reflecting system through a deflecting device of variable deflection, which permits of displacing parallel to the base-line the image formed from the pencil system and presented to the observer, and these two deflecting devices are coupled in such amanner that, for the purpose of altering the d1- rection of outlook, the two images can be displaced jointly by a small amount in the direction of the base-line. Such a joint dis-`A placement of the two images results in a disadjustment of the instrument, when the amount, by which the images are displaced, is not the same for both images. Hence, if the instrument is to give correctjreadings for any direction of outlook, it is necessary for the parts of the instrument, serving for the joint displacement of the images, to be of an accuracy that can only be realized with difficulty in practice when manufacturing such telemeters. These difficulties certainly may be avoided, by using not one pair of'deflecting devices of variable deflection, but several pairs of deflecting devices having a different but invariable deflection. For displacing the images, one such pair of deflecting devices can then be replaced by another pair, whereby, it is true, the displacement of the images is caused to proceed by jerks.

According to the present invention the deflection of the ray pencil systems required for the displacement of-the images is effected not by special, deflecting devices, which are separate from the objective reflecting systems, but by the said deflecting devices themselves, and for this purpose the telemeter contains at either end of the base-line a number of objective reflecting systems differing from one another as regards their'deflection, which may be introduced one after another into the path of the rays, the sum derived from the angle of l deflection of an objective reflecting system at one end of the base-line and the angle ofdeflection of the objective reflecting systembelonging to it at the other end of the base line being the same for all the pairs of objective reflecting systems. n-such a telemeter the direction of outlook is altered by passing from one pair of objective reflecting systems to another pair.

Il a telemeter, in which for the purpose of taking al measurement the image of an object, the range of which is to be found, is to be brought to a particular part of the imagelfield, c. g. next to the image of the part of a stereoscopic distance scale appertaining thereto, be fitted in accordance with the invention, it is necessary, as, just 'through the interchange of the objective reflecting systems, the direction of outlook can be altered only by jerks, to journal the instrumentin such a manner as to be rotatable in the plane of triangulation by a small amount, should it not be deemed preferable to fit the telemeter in addition with a pair of deflecting devices, which is separate from the objective reflecting systems and allows Within comparatively narrow limits of an additional constant displace: ment of the images.l

The annexed drawing shows a constructional form of a coincidence telemeter according to the invention, in which the two images presented to the observer are erect, Figure l being an elevation in part section and Fig. 2 a `plan view.

The objective lenses a, a are mounted each in one of the tubes b1 and b2, which are connected together by a central body c containing an ocular d1, d2 and a separating prism system e1, e2. The cement layer e0 between the two prisms e1 and e2 is formed as to its upper half as a separating layer reflecting both ways. A glass wedge f, which can be displaced by means of a milled head g, serves for measuring. The scale f, which is fixed tothe Wedge f, and the index f1 are visible through a window it. In front of each of the objective lenses a there is located a group of five optical squares z', 1, 2, 3, 4, each square having a different deflection and each group being fixed on a plate 7c, which is parallel to the plane of triangulation, in such a manner that by rotating the plate about an axis perpendicular to the said plane each of the five optical squares may be ,brought into its effective position. By means ol' toothed wheels l1, Z', Z3, Z* and of tivo pairs ol bevel wheels m1, m, of which the wheels 111.1 are fixed on a shaft n journaledin bodies o* and o2 fixed to the tubes b1 and b2, the` two plates L' are coupled together in such a manner that they rotate in opposite directions, when the shaft n is rotated by means of a `milled head nl, and that an optical square belonging to oneend of the base-line always becomes effective simultaneously with one belonging to' the other end. The" size of the angles of deflection rof the optical squares is in the present case so vchosen that.

the sum derived from the angle of deflection of' a reflecting system at the oneend of the base-line and the angle ofdeflection of the reflecting system belongingto it at the other. .i end of the base-line amounts for eachl of the live pairs of optical squaresto 1805?; rlhe optical squares z', which are in thedravving1iny'- their effectivev position, each 4deflect the entering ray pencil system byj909; hence,vWhen theyv are in the said position, the direction of outlook is approximately perpendicular to the base-line of the telemeter. y".l`h'e"o}.` ti

cal squares-are so disposed on the plates lc,

\ cause an alteration ofthe direction of outlook 1n one sense, and those optical squares (corresponding tothe aboveassumption 3 and 4 of lthe left-hand disk and 1 and 2 of rthe right-hand disk), which loan be made operative by a vrotation of the shaft n in the opposite direction to the former rotation, cause an alteration of the direction of outlook in the other sense. The angle of deflection peculiar to each optical square is so chosen that, on a rotation of the disks c out of the position shown taking place, the direction of outlook becomes more and more in.

l In ai horizontal telemeter a` base-line within'thein'strument, la kmeasuring device, an ocularsystem, an ocular reflecting system, at either side of the said ocular reflecting system anobjective `lens system, at .either end ofthel said base-,line agroup of objective reflecting systems, means for bringing the said reflectingsysteinsfone after another into the path ofthe rays, each such system having a different deflectionto the others and the sum derived from the angle of deflection of an objective reflecting System at one end of the base-line and the angle of deflection of the objective reflecting system belonging to it at the other end of the base-line being the same for all pairs of objective reflecting systems.

OTT() EPPENSTElN.